In a case of specifying information which matches with a purpose from a vast amount of data present in a database, network or the like, a search engine to search for information by designating a keyword or the like is generally used. However, with simple designation of a keyword, there may be a huge amount of information hit, so that the search engine cannot narrow down information wanted by the user. As a more efficient method of narrowing down information, there has been proposed a retrieval method which uses the composition of a user who makes a search, such as the behavior history or interest.
Patent Document 1 discloses a technique capable of specifying information which reflects the behavior pattern or interest of a user by grasping the profile of the user and information to be searched as vectors having coordinate values and narrowing down information based on the similarity of vectors. With the use of Patent Document 1, when a user searches for books at a book sales site, for example, it is possible to present the user with information relating to recommendable books which reflect the purchase history of the user.
Patent Document 2 discloses a technique capable of selecting information close to the interest of a user by creating a database reflecting the interest of the user and reflecting information stored in the database on narrowing down information. With the use of Patent Document 2, even a beginner of information search or a user who does not have enough knowledge about information to be searched can easily obtain a search result close to what the user desires.
The retrieval methods that use the behavior history or interest of a user are effective for the user to quickly get information needed. In a case where the intention of a user is clear, such as a business purpose or a learning purpose, the use of those methods can allow information to be efficiently specified. When a user tries to search for contents for entertainment, such as game software, it is not always the case that the intention of the user is clear, so that the use of the aforementioned retrieval methods with priority given only to efficiency may lose the entertainment.
For example, there is a case where a user is not intended to play a particular game when he/she wants to enjoy a game in free time by connecting a cellular phone to a network. There is a case where a user wants recommendation of game software the user may prefer from game softwares downloadable from a server. In such a case, the server may mechanically match downloadable game softwares with data relating to the preference of the user and recommend game softwares with high matching in order. If the intention of the user is vague, however, recommendation of game softwares which do not match with the preference but may give appeal, rather than listing game softwares with similar inclination, increases the unexpectedness of recommended game softwares, resulting in higher entertainment.
In a case where a user searches for contents with a specific intention, the server likewise may rather recommend contents of a category which do not belong to a category closest to the user's intention but have some kind of relation with the user's preference, than recommend contents closer to the user's intention in order. In this case, the user can get to contents which the user has not noticed as his or her preference so far, and the unexpectedness of recommended game softwares increases, thus resulting in higher entertainment.
A user can retrieve unexpected and entertaining information as contents which do not match with the direct searching purpose or the preference of the user within a range relating to the user's preference are selected and recommended while basically narrowing down contents which would be recommended according to the user's searching intention or preference. The user can enjoy retrieving unexpected and entertaining information as if the user stopped by interesting shops on the way to the destination and enjoyed window shopping.
Patent Document 1: Japanese Patent Application Laid-Open No. 2001-265808
Patent Document 2: Japanese Patent Application Laid-Open No. 2003-58571